Information recording medium, and method and apparatus for managing defect thereof

ABSTRACT

An information recording medium includes a disk information area; a user area including a plurality of sectors; and a spare area including at least one sector which, when at least one of the plurality of sectors included in the user area is a defective sector, is usable instead of the at least one defective sector. The spare area is located radially inward from the user area. A physical sector number of a sector to which a logical sector number “0” is assigned, among the plurality of sectors included in the user area and the at least one sector included in the spare area, is recorded in the disk information area.

This application is a continuation of application Ser. No. 09/369,815,filed Aug. 6, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information recording medium, and amethod and an apparatus for managing a defect thereof.

2. Description of the Related Art

A representative information recording medium having a sector structureis an optical disk. Recently, the density and capacity of optical diskshave been improved. Therefore, it is important to guarantee thereliability of optical disks.

FIG. 23 shows a logical structure of a conventional optical disk.

As shown in FIG. 23, the optical disk includes two disk informationareas 4 and a data recording area 5. The data recording area 5 includesa user area 6 and a spare area 8. The spare area 8 is located radiallyoutward from the user area 6 on the optical disk.

The user area 6 includes a system reservation area 11, a FAT (FileAllocation Table) area 12, a root directory area 13, and a file dataarea 14. The system reservation area 11, the FAT area 12, and the rootdirectory area 13 are collectively referred to as a file management area10. A first sector of the file management area 10 is located as a sectorto which logical sector number “0” (LSN:0) is assigned.

Methods for managing defects of an optical disk are included inISO/IEC10090 standards (hereinafter, referred to as the “ISO standards”)provided by the International Organization of Standardization regarding90 mm optical disks.

Hereinafter, two methods for managing defects included in the ISOstandards are described.

One of the methods is based on a slipping replacement algorithm. Theother method is based on a linear replacement algorithm. Thesealgorithms are described in Chapter 19 of the ISO standards.

FIG. 24 is a conceptual view of the conventional slipping replacementalgorithm. In FIG. 24, each of the rectangle boxes represents a sector.Characters in each sector represent a logical sector number (LSN)assigned to the sector. The rectangle boxes having an LSN representnormal sectors, and the hatched rectangle box represents a defectivesector.

Reference numeral 2401 represents a sequence of sectors including nodefective sector in the user area 6, and reference numeral 2402represents a sequence of sectors including one defective sector in theuser area 6.

When a first sector in the user area 6 is a normal sector, LSN:0 isassigned thereto. LSNs are assigned to a plurality of sectors includedin the user area 6 in an increasing order from the first sector to whichLSN:0 is assigned.

When the user area 6 includes no defective sector, LSN:0 through LSN:mare assigned to the sectors in the user area 6 sequentially from thefirst sector to a last sector thereof as represented by the sequence ofsectors 2401.

If a sector in the sequence of sectors 2401 to which LSN:i is assignedwas a defective sector, the assignment of the LSNs is changed so thatLSN:i is not assigned to the defective sector but to a sectorimmediately subsequent to the defective sector. Thus, the assignment ofthe LSNs are slipped by one sector in the direction toward the sparearea 8 from the user area 6. As a result, the last LSN:m is assigned toa first sector in the spare area 8 as represented by the sequence ofsectors 2402.

FIG. 25 shows the correspondence between the physical sector numbers andthe LSNs after the slipping replacement algorithm described withreference to FIG. 24 is executed. The horizontal axis represents thephysical sector number, and the vertical axis represents the LSN. InFIG. 25, chain line 2501 indicates the correspondence between thephysical sector numbers and the LSNs when the user area 6 includes nodefective sector. Solid line 2502 indicates the correspondence betweenthe physical sector numbers and the LSNs when the user area 6 includesdefective sectors I through IV.

As shown in FIG. 25, no LSN is assigned to the defective sectors Ithrough IV. The assignment of the LSNs is slipped in the directiontoward an outer portion from an inner portion of the optical disk (i.e.,in the increasing direction of the physical sector number). As a result,the LSNs are assigned to a part of the sectors in the spare area 8 whichis located immediately after the user area 6.

An advantage of the slipping replacement algorithm is that a delay inaccess caused by a defective sector is relatively small. One defectivesector delays the access merely by a part of the rotation correspondingto one sector. A disadvantage of the slipping replacement algorithm isthat the assignment of all the LSNs is slipped after one defectivesector. An upper level apparatus such as, for example, a host personalcomputer identifies sectors by LSNs assigned thereto. When theassignment of the LSNs to the sectors is slipped, the host computercannot manage user data recorded in the optical disk. Accordingly, theslipping replacement algorithm is not usable after the user data isrecorded in the optical disk.

FIG. 26 is a conceptual view of the conventional linear replacementalgorithm. In FIG. 26, each of the rectangle boxes represents a sector.Characters in each sector represent a logical sector number (LSN)assigned to the sector. The rectangle boxes having an LSN representnormal sectors, and the hatched rectangle box represents a defectivesector.

Reference numeral 2601 represents a sequence of sectors including nodefective sector in the user area 6, and reference numeral 2602represents a sequence of sectors including one defective sector in theuser area 6.

If a sector in the sequence of sectors 2601 to which LSN:i is assignedwas a defective sector, the assignment of the LSNs is changed so thatLSN:i is not assigned to the defective sector. Instead, LSN:i isassigned to, among a plurality of sectors included in the spare area 8,a sector which is unused yet and has a minimum physical sector number(e.g., a first sector of the spare area 8) as represented by thesequence of sectors 2602. Thus, the defective sector in the user area 6is replaced with a sector in the spare area 8.

FIG. 27 shows the correspondence between the physical sector numbers andthe LSNs after the linear replacement algorithm described with referenceto FIG. 26 is executed. The horizontal axis represents the physicalsector number, and the vertical axis represents the LSN. In FIG. 27, thesolid line 2701 indicates the correspondence between the physical sectornumbers and the LSNs when the user area 6 includes two defectivesectors. The two defective sectors in the user area 6 are replaced byreplacing sectors in the spare area 8, respectively.

An advantage of the linear replacement algorithm is that replacement ofa defective sector does not influence other sectors since defectivesectors and replacing sectors correspond to each other one to one. Adisadvantage of the linear replacement algorithm is that a delay inaccess caused by a defective sector is relatively large. Accessing areplacing sector instead of a defective sector requires a seek operationover a relatively long distance.

As can be appreciated, the advantage and disadvantage of the linearreplacement algorithm are converse to the advantage and disadvantage ofthe slipping replacement algorithm.

FIG. 28 shows an example of assignment of the LSNs to the sectors. Inthe example shown in FIG. 28, it is assumed that the user area 6 has asize of 100000, the spare area 8 has a size of 10000, and the user area6 includes four defective sectors.

LSNs are assigned to the sectors in accordance with the slippingreplacement algorithm described above.

First, LSN:0, which is a first LSN, is assigned to a sector having aphysical sector number:0. Then, LSNs are assigned to the sectors in anincreasing order toward an outer portion from an inner portion of theoptical disk (i.e. toward the spare area 8 from the user area 6). No LSNis assigned to the defective sectors. The LSN which would be assigned toeach defective sector is assigned to a sector immediately subsequentthereto. As a result, the assignment of the LSNs is slipped in thedirection toward an outer portion from an inner portion of the opticaldisk by the number of the defective sectors.

In the example shown in FIG. 28, the user area 6 includes four defectivesectors I through IV as described above. LSN:99996 through LSN:99999,which would be assigned to the four sectors I through IV if the foursectors I through IV were not defective, are assigned to four sectors inthe spare area 8, respectively, having physical sector numbers of 100000through 100003. The reason for this is that the assignment of the LSNsis slipped by the number of the defective sectors (four in thisexample).

In FIG. 28, the sectors in the spare area 8 having the physical sectornumbers of 100004 through 109999 are collectively referred to as an “LRspare area”. The LR spare area is defined as an area in the spare area 8to which no LSN is assigned. The LR spare area is used in the linearreplacement algorithm as a replacing area.

As shown in FIG. 27, the conventional linear replacement algorithm has aproblem in that, when a sector having a small physical sector number isdefected as a defective sector, a delay in access caused by thedefective sector is relatively large since the distance between thedefective sector and the replacing sector is relatively long. Since thefile management area 10 located in the vicinity of the sector to whichLSN:0 is assigned is accessed each time a file is recorded, a defectivesector in the file management area 10 may directly cause undesirablereduction in the access speed to the optical disk. The file managementarea 10, which is frequently accessed, is expected to have the highestpossibility of generating a defective sector.

In order to find the first address of the replacing area (i.e., LR sparearea) used in the linear replacement algorithm, the number of sectors bywhich the assignment of the LSNs is slipped in the slipping replacementalgorithm needs to be calculated. The amount of calculation increases asthe disk capacity increases.

SUMMARY OF THE INVENTION

According to one aspect of the invention, an information recordingmedium includes a disk information area; a user area including aplurality of sectors; and a spare area including at least one sectorwhich, when at least one of the plurality of sectors included in theuser area is a defective sector, is usable instead of the at least onedefective sector. The spare area is located radially inward from theuser area. A physical sector number of a sector to which a logicalsector number “0” is assigned, among the plurality of sectors includedin the user area and the at least one sector included in the spare area,is recorded in the disk information area.

In one embodiment of the invention, a logical sector number is assignedto the sectors included in the user area other than the at least onedefective sector in a decreasing order from the sector to which a lastlogical sector number is assigned.

In one embodiment of the invention, a physical sector number of the atleast one defective sector is recorded in the disk information area.

In one embodiment of the invention, the combined user area and sparearea is divided into a plurality of zones, and a logical sector numberassigned to a first sector of each of the plurality of zones is recordedin the disk information area.

In one embodiment of the invention, the combined user area and sparearea is divided into a plurality of zones. Data recorded in theinformation recording medium is managed on an ECC block-by-ECC blockbasis. A logical sector number is assigned to the sectors included inthe user area other than the at least one defective sector so that afirst sector of each of the plurality of zones matches a first sector ofa corresponding ECC block.

According to another aspect of the invention, a method for managing adefect of an information recording medium including a disk informationarea; a user area including a plurality of sectors; and a spare areaincluding at least one sector which, when at least one of the pluralityof sectors included in the user area is a defective sector, is usableinstead of the at least one defective sector, the spare area beinglocated radially inward from the user area. The method includes thesteps of (a) assigning a last logical sector number to one of theplurality of sectors included in the user area; (b) calculating alocation fulfilling a prescribed capacity, with a location of the sectorto which the last logical sector number is assigned being fixed; (c)assigning a logical sector number “0” to a sector positioned at thelocation calculated by the step (b); and (d) recording a physical sectornumber of the sector to which the logical sector number “0” is assignedin the disk information area.

In one embodiment of the invention, the step (b) includes the steps of(b-1) detecting the at least one defective sector included in the userarea; and (b-2) calculating the location fulfilling the prescribedcapacity based on the number of the at least one defective sectordetected in the step (b-1).

In one embodiment of the invention, the method further includes the stepof (e) recording the at least one defective sector detected in the step(b-1) in the information recording medium.

In one embodiment of the invention, the combined user area and sparearea is divided into a plurality of zones, and the method furtherincludes the step of (f) recording a logical sector number assigned to afirst sector of each of the plurality of zones in the disk informationarea.

In one embodiment of the invention, the combined user area and sparearea is divided into a plurality of zones. Data recorded in theinformation recording medium is managed on an ECC block-by-ECC blockbasis. The method further includes the step of (g) assigning a logicalsector number to the sectors included in the user area other than the atleast one defective sector so that a first sector of each of theplurality of zones matches a first sector of a corresponding ECC block.

According to still another aspect of the invention, an apparatus formanaging a defect of an information recording medium including a diskinformation area; a user area including a plurality of sectors; and aspare area including at least one sector which, when at least one of theplurality of sectors included in the user area is a defective sector, isusable instead of the at least one defective sector, the spare areabeing located radially inward from the user area. The apparatus executesdefect management processing, which comprises the steps of (a) assigninga last logical sector number to one of the plurality of sectors includedin the user area; (b) calculating a location fulfilling a prescribedcapacity, with a location of the sector to which the last logical sectornumber is assigned being fixed; (c) assigning a logical sector number“0” to a sector positioned at the location obtained by the step (b); and(d) recording a physical sector number of the sector to which thelogical sector number “0” is assigned in the disk information area.

In one embodiment of the invention, the step (b) includes the steps of(b-1) detecting the at least one defective sector included in the userarea; and (b-2) calculating the location fulfilling the prescribedcapacity based on the number of the at least one defective sectordetected in the step (b-1).

In one embodiment of the invention, the defect management processingfurther includes the step of (e) recording the at least one defectivesector detected in the step (b-1) in the information recording medium.

In one embodiment of the invention, the combined user area and sparearea is divided into a plurality of zones. The defect managementprocessing further includes the step of (f) recording a logical sectornumber assigned to a first sector of each of the plurality of zones inthe disk information area.

In one embodiment of the invention, wherein the combined user area andspare area is divided into a plurality of zones, data recorded in theinformation recording medium is managed on an ECC block-by-ECC blockbasis, and the defect management processing further includes the step of(g) assigning a logical sector number to the sectors included in theuser area other than the at least one defective sector so that a firstsector of each of the plurality of zones matches a first sector of acorresponding ECC block.

Thus, the invention described herein makes possible the advantages ofproviding (1) an information recording medium and a method and anapparatus for managing a defect thereof for keeping a delay in accessrelatively small even when a defective sector is detected in a filemanagement area located in the vicinity of a sector to which LSN:0 isassigned; and (2) an information recording medium, and a method and anapparatus for managing a defect thereof for allowing the location of anLR spare area to be found with substantially no calculation.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a block diagram showing a structure of an information processingsystem in an example according to the present invention;

FIG. 2 is a diagram showing a physical structure of an optical disk 1;

FIG. 3 is a diagram showing a logical structure of the optical disk 1;

FIG. 4 is a diagram showing a structure of a DMA:

FIG. 5 is a diagram showing a structure of a DDS;

FIG. 6A is a diagram showing a structure of a PDL;

FIG. 6B is a diagram showing a structure of an SDL;

FIG. 7 is a conceptual view of a slipping replacement algorithmaccording to the present invention;

FIG. 8 is a graph illustrating the correspondence between physicalsector numbers and LSNs after the slipping replacement algorithm shownin FIG. 7 is executed;

FIG. 9 is a conceptual view of a linear replacement algorithm accordingto the present invention;

FIG. 10 is a graph illustrating the correspondence between physicalsector numbers and LSNs after the linear replacement algorithm shown inFIG. 7 is executed;

FIG. 11 is a flowchart illustrating a process of examination of a disk;

FIG. 12 is a flowchart illustrating a process of finding a physicalsector number of a sector to which LSN:0 is assigned;

FIG. 13 is a flowchart illustrating a process of the function FUNC (TOP,END) shown in FIG. 12;

FIG. 14 is a diagram showing an example of LSNs assigned to the sectorsafter the examination of the disk;

FIG. 15 is a flowchart illustrating a process of recording data to theoptical disk 1;

FIG. 16 is a flowchart illustrating a process of replacement processingexecuted in steps 1508 and 1509 shown in FIG. 15;

FIG. 17 is a graph illustrating the correspondence between physicalsector numbers and LSNs after the slipping replacement algorithm shownin FIG. 7 and the linear replacement algorithm shown in FIG. 9 areexecuted;

FIG. 18 is a flowchart illustrating a process of recording an AV file inthe optical disk 1;

FIG. 19 is a diagram showing a structure of a data recording area havingthe AV file recorded therein;

FIG. 20 is a diagram showing a physical structure of an optical diskhaving two zones;

FIG. 21 is a graph illustrating the correspondence between physicalsector numbers and LSNs of the optical disk shown in FIG. 20 after theslipping replacement algorithm shown in FIG. 7 is executed;

FIG. 22A is a conceptual view of a slipping replacement algorithmaccording to the present invention;

FIG. 22B is a graph illustrating the correspondence between physicalsector numbers and LSNs after the slipping replacement algorithm shownin FIG. 22A is executed;

FIG. 22C is a diagram showing a structure of a DDS of the optical diskshown in FIG. 20;

FIG. 23 is a diagram showing a logical structure of a conventionaloptical disk;

FIG. 24 is a conceptual view of a conventional slipping replacementalgorithm;

FIG. 25 is a graph illustrating the correspondence between physicalsector numbers and LSNs of the conventional optical disk after theconventional slipping replacement algorithm is executed;

FIG. 26 is a conceptual view of a conventional linear replacementalgorithm;

FIG. 27 is a graph illustrating the correspondence between physicalsector numbers and LSNs of the conventional optical disk after theconventional linear replacement algorithm is executed; and

FIG. 28 is a diagram showing an example of LSNs assigned to the sectorsof the conventional optical disk.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the present invention will be described by way ofillustrative examples with reference to the accompanying drawings.

EXAMPLE 1 1. Structure of an Information Processing System

FIG. 1 shows a structure of an information processing system in a firstexample according to the present invention. The information processingsystem includes an upper level apparatus 200 and a disk recording andreproduction apparatus 100. The disk recording and reproductionapparatus 100 records information to a rewritable optical disk 1 orreproduces information recorded in the optical disk 1 in accordance witha command from the upper level apparatus 200. The upper level apparatus200 is, for example, a personal computer.

The upper level apparatus 200 includes a CPU 201, a main memory 204, abus interface (bus I/F) 203, a processor bus 202, an I/O bus 205, a harddisk device (HDD) 206, a display processing section 207, and an inputsection 208. The upper level apparatus 200 is connected to the diskrecording and reproduction apparatus 100 through the I/O bus 205.

The processor bus 202 is a high speed bus through which the CPU 201accesses the main memory 204. The processor bus 202 is connected to theI/O bus 205 through the bus I/F 203.

In the example shown in FIG. 1, the I/O bus 205 is a personal computerextended bus such as, for example, a PCI bus or an ISA bus. The I/O bus205 can be an arbitrary multi-purpose bus of, for example, SCSI (SmallComputer System Interface), ATA (At Attachment), USB (Universal SerialBus), or IEEE1394.

The display processing section 207 converts display information sentthrough the I/O bus 205 into a signal such as, for example, an RGBsignal, and outputs the resultant signal.

The input section 208 receives data from an input device such as, forexample, a keyboard or a mouse and sends the data to the CPU 201 throughthe I/O bus 205.

The HDD 206 is a secondary memory device for inputting and outputtingdata with the main memory 204 through the I/O bus 205. The HDD 206 hasan operating system such as, for example, MS-DOS® or Windows® and aprogram file stored therein. The main memory 204 is loaded with theoperating system and the program file, and the operating system and theprogram file are operated by the CPU 201 in accordance with aninstruction from the user. The operation results are displayed on ascreen by the display processing section 207.

The disk recording and reproduction apparatus 100 includes amicroprocessor 101, a data recording and reproduction control section102, a bus control circuit 103 and a memory 104.

The microprocessor 101 controls the elements in the disk recording andreproduction apparatus 100 in accordance with a control program built inthe microprocessor 101 to execute various types of processing. Defectmanagement processing and replacement processing described below areexecuted by the microprocessor 101.

The data recording and reproduction control section 102 controlsrecording of data to and reproduction of data from the optical disk 1 inaccordance with an instruction from the microprocessor 101. The datarecording and reproduction control section 102 adds an error correctioncode to the data during recording, and executes error detectionprocessing and error correction processing during reproduction. Ingeneral, data coded by encoding processing such as, for example, CRC orECC is recorded in the optical disk 1.

The bus control circuit 103 receives a command from the upper levelapparatus 200 through the I/O bus 205, and transmits and receives datawith the upper level apparatus 200 through the I/O bus 205.

The memory 104 is used for storing data during various types ofprocessing executed by the disk recording and reproduction apparatus100. For example, the memory 104 has an area used as an intermediatebuffer during data recording or reproduction and an area used by thedata recording and reproduction control section 102 for the errorcorrection processing.

The optical disk 1 is a circular information recording medium to whichdata can be recorded and from which data can be reproduced. Usable asthe optical disk 1 is an arbitrary information recording medium such as,for example, a DVD-RAM disk. Data recording and reproduction isperformed on a sector-by-sector basis or on a block-by-block basis.

2. Physical Structure of the Optical Disk 1

FIG. 2 shows a physical structure of the optical disk 1. The circularoptical disk 1 has a plurality of concentric tracks or a spiral track 2formed therein. Each of the tracks or track 2 is divided into aplurality of sectors 3. The optical disk 1 includes at least one diskinformation area 4 and a data recording area 5.

The disk information area 4 has, for example, a parameter required foraccessing the optical disk 1. In the example shown in FIG. 2, theoptical disk 1 has one disk information area 4 in an innermost part andone disk information area 4 in an outermost part thereof. The diskinformation area 4 in the innermost part is also referred to as a“lead-in area”. The disk information area 4 in the outermost part isalso referred to as a “lead-out area”.

The data recording area 5 has data recorded therein. Data is recorded toand reproduced from the data recording area 5. Each of all sectors inthe data recording area 5 has an absolute address referred to as aphysical sector number pre-assigned thereto.

3. Logical Structure of the Optical Disk 1

FIG. 3 shows a logical structure of the optical disk 1. The datarecording area 5 includes a user area 6 and a spare area 7.

The user area 6 is prepared for storing user data. Usually, the userdata is stored in the user area 6. Each of sectors included in the userarea 6 has a logical sector number (LSN) assigned thereto, by which thesector is accessed. The upper level apparatus 200 shown in FIG. 1accesses a sector in the optical disk 1 using the LSN to performrecording and reproduction of data.

The spare area 7 includes at least on e sector which, when a sector inthe user area 6 becomes defective, can be used in place of the defectivesector. A sector in the user area 6 becomes defective by, for example,scratches, stains or quality decline of the user area 6 of the opticaldisk 1. The spare area 7 is located radially inward from the user area6. Preferably, the spare area 7 is located immediately radially inwardfrom the user area 6.

The user area 6 includes a system reservation area 11, a FAT (FileAllocation Table) area 12, a root directory area 13, and a file dataarea 14. Such a structure is in conformity to an MS-DOS file system. Thestructure shown in FIG. 3 is merely an example.

The system reservation area 11 has parameter information and volumeinformation of the optical disk 1 stored therein as a boot sector. Suchinformation can be referred to by the upper level apparatus 200.

In order for the upper level apparatus 200 to access the optical disk 1,the upper level apparatus 200 needs to access the system reservationarea 11 with certainty. A logical sector number “0” (LSN:0) is assignedto a first sector of the system reservation area 11. Sizes and locationsof entries in the system reservation area 11 are predetermined.

The FAT area 12 has stored therein location information indicatinglocations of files and directories in the file data area 14 and a FATindicating locations of empty areas.

The root directory area 13 has entry information on files andsub-directories stored therein. The entry information includes, forexample, a file name, directory name, file attribute and updating dateinformation.

The system reservation area 11, FAT area 12, and root directory area 13are collectively referred to as a file management area 10. The filemanagement area 10 is positioned at a location on the optical disk 1corresponding to a fixed LSN.

The file data area 14 has stored therein data which represents adirectory associated with the root directory and data which represents afile. As described above, in order that the upper level apparatus 200may access data stored in the file data area 14, the upper levelapparatus 200 needs to access the file management area 10 beforeaccessing the file data area 14.

4. Method for Managing a Defect of the Optical Disk 1

In order to manage a defective sector in the optical disk 1, a PDL(Primary Defect List) and an SDL (Secondary Defect List) are used.

When initializing the optical disk 1, a defective sector is detected inaccordance with the slipping replacement algorithm. The detecteddefective sector is registered in the PDL. When recording data to theoptical disk 1, a defective sector is detected in accordance with thelinear replacement algorithm. The detected defective sector isregistered in the SDL. The reliability of the optical disk 1 isguaranteed by registering the defective sector in the PDL or SDL.

The PDL and SDL are stored in a DMA (Defect Management Area). A DDS(Disk Definition Structure) is also stored in the DMA.

4.1. Structure of the DMA

FIG. 4 shows a structure of the DMA. The DMA is a part of the diskinformation area 4 shown in FIGS. 2 and 3.

The DMA is described as DMA1 through DMA4 in Chapter 18 of ISO standardsregarding the layout in an optical disk. Two out of four DMAs (e.g.,DMA1 and DMA2) are located in the disk information area 4 arranged atthe inner portion of the optical disk, and the remaining two DMAs (e.g.,DMA3 and DMA4) are located in the disk information area 4 arranged atthe outer portion of the optical disk 1 (FIG. 3). In the four DMAs,identical information is multiplex-recorded in order to compensate for adefective sector in a DMA which cannot be replaced with a replacingsector.

FIG. 4 shows an example of the disk information area 4 arranged at theinner portion of the optical disk 1, which includes DMA1 and DMA2 amongthe four DMAs.

The DMA1 has a DDS, a PDL and an SDL stored therein. DMA2 through DMA4have an identical structure with that of DMA1.

4.1.1 Structure of the DDS

FIG. 5 shows a structure of the DDS.

The DDS includes a header. The header includes, for example, anidentifier indicating the information is the DDS. The DDS furtherincludes an entry for storing partition information, an entry forstoring PDL location information, an entry for storing SDL locationinformation, and an entry for storing a physical sector number of asector to which the logical sector number “0” (LSN:0) is assigned to.

4.1.2 Structure of the PDL

FIG. 6A shows a structure of the PDL.

The PDL includes a header and a plurality of entries (first through n'thentries in the example shown in FIG. 6A). The header includes, forexample, an identifier indicating the information is the PDL and thenumber of entries of defective sectors registered in the PDL. Each entrystores a physical sector number of the defective sector.

4.1.3. Structure of the SDL

FIG. 6B shows a structure of the SDL.

The SDL includes a header and a plurality of entries (first through n'thentries in the example shown in FIG. 6B). The header includes, forexample, an identifier indicating the information is the SDL and thenumber of entries of defective sectors registered in the SDL. Each entryincludes a physical sector number of the defective sector and thephysical sector number of the replacing sector in which data is recordedinstead of the defective sector. The SDL is different from the PDL inhaving the physical sector number of the replacing sector.

4.2 Slipping Replacement Algorithm

FIG. 7 is a conceptual view of a slipping replacement algorithm executedby the disk recording and reproduction apparatus 100 (FIG. 1) in thefirst example according to the present invention. In FIG. 7, each of therectangle boxes represents a sector. Characters in each sector representan LSN assigned to the sector. The rectangle boxes having an LSNrepresent normal sectors, and the hatched rectangle box represents adefective sector.

Reference numeral 71 represents a sequence of sectors including nodefective sector registered in the PDL, and reference numeral 72represents a sequence of sectors including one defective sectorregistered in the PDL.

When a last sector in the user area 6 is a normal sector, LSN:m isassigned to the last sector. LSNs are assigned to a plurality of sectorsincluded in the user area 6 in a decreasing order from the last sectorto which LSN:m is assigned.

When the PDL includes no defective sector, LSN:m through LSN:0 areassigned to the sectors in the user area 6 sequentially from the lastsector to a first sector thereof as represented by the sequence ofsectors 71.

If a sector in the sequence of sectors 71 to which LSN:i is assigned wasa defective sector, the assignment of the LSNs is changed so that LSN:iis not assigned to the defective sector but to a sector immediatelybefore the defective sector. Thus, the assignment of the LSNs is slippedby one sector in the direction toward the spare area 7 from the userarea 6. As a result, the last sector LSN:0 is assigned to a last sectorof the spare area 7 as represented by the sequence of sectors 72.

FIG. 8 shows the correspondence between the physical sector numbers andthe LSNs after the slipping replacement algorithm described withreference to FIG. 7 is executed. The horizontal axis represents thephysical sector number, and the vertical axis represents the LSN. InFIG. 8, chain line 81 indicates the correspondence between the physicalsector numbers and the LSNs when the user area 6 includes no defectivesector. Solid line 82 indicates the correspondence between the physicalsector numbers and the LSNs when the user area 6 includes defectivesectors I through IV.

As shown in FIG. 8, no LSN is assigned to the defective sectors Ithrough IV. The assignment of the LSNs are slipped in the directiontoward an inner portion from an outer portion (i.e., in the decreasingdirection of the physical sector number). As a result, an LSN isassigned to a part of the spare area 7 located immediately radiallyinward from the user area 6.

As described above, when one or more defective sectors are registered inthe PDL, the assignment of the LSNs is slipped in the direction towardan inner portion from an outer portion of the optical disk 1, with thelocation of the sector to which the last LSN is assigned being fixed. Asa result, LSNs are assigned to one or more sectors in the spare area 7located radially inward from the user area 6 of the optical disk 1. Thenumber of the sectors in the spare area 7 to which the LSNs are assignedequals the number of the defective sectors in the user area 6.

The location of a sector to which the LSN:0 is to be assigned iscalculated so as to fulfill a prescribed capacity (e.g., 4.7 GB), withthe location of the sector to which the last LSN is assigned beingfixed. The calculation is performed based on the number of the defectivesectors detected in the user area 6. LSN:0 is assigned to the sectorpositioned at the calculated location. The prescribed capacity is thecapacity which is required to be secured as an area in which user datacan be recorded. As described above, when the user area 6 includes oneor more defective sectors, a prescribed capacity (e.g., 4.7 GB) canalways be secured by using a part of the spare area 7 instead of theuser area 6.

When the last sector of the user area 6 is a normal sector, the last LSNis assigned to the last sector of the user area 6. When the last sectorof the user area 6 is a defective sector, the last LSN is assigned to anormal sector closest to the last sector.

The physical sector number of the sector to which LSN:0 is assigned isstored in an entry in the DDS (FIG. 5). The entry is referred to by theupper level apparatus 200 for recording data in the optical disk 1. Byreferring to the entry, the upper level apparatus 200 can obtain thephysical sector number corresponding to LSN:0 without performing acalculation. As a result, a high speed access to the sector having LSN:0assigned thereto is realized.

For recording data in the optical disk 1, the upper level apparatus 200needs to access the sector having LSN:0 assigned thereto, withcertainty. Accordingly, the capability of accessing the sector to whichLSN:0 is assigned at a high speed is very effective in accessing theoptical disk 1 at a high speed.

4.3 Linear Replacement Algorithm

FIG. 9 is a conceptual view of a linear replacement algorithm executedby the disk recording and reproduction apparatus 100 (FIG. 1). In FIG.9, the rectangle boxes each represent a sector. Characters in eachsector represent an LSN assigned to the sector. The rectangle boxeshaving an LSN represent normal sectors, and the hatched rectangle boxrepresents a defective sector.

Reference numeral 91 represents a sequence of sectors including nodefective sector in the SDL, and reference numeral 92 represents asequence of sectors including one defective sector in the SDL.

If a sector in the sequence of sectors 91 to which LSN:i is assigned wasa defective sector, the assignment of the LSNs is changed so that LSN:iis not assigned to the defective sector. Instead, LSN:i is assigned to asector which is unused yet and has a minimum physical sector number(e.g., a first sector of the LR spare area; described later withreference to FIG. 14) as represented by the sequence of sectors 92.Thus, the defective sector in the user area 6 is replaced with a sectorin the LR spare area.

LSN:i can be assigned to, among the plurality of sectors included in theLR spare area, a sector which has not been used yet and has a maximumphysical sector number (e.g., a sector having a physical sector numberwhich is less by 1 than the physical sector number of the sector towhich LSN:0 is assigned). It is not important in which order the sectorsin the LR spare area are used.

FIG. 10 shows the correspondence between the physical sector numbers andthe LSNs after the linear replacement algorithm described with referenceto FIG. 9 is executed. The horizontal axis represents the physicalsector number, and the vertical axis represents the LSN. In FIG. 10,solid line 1001 indicates the correspondence between the physical sectornumbers and the LSNs when the user area 6 includes two defectivesectors.

It can be appreciated from FIG. 10 that the distance between thedefective sector and the replacing sector (number of physical sectors)is significantly reduced compared to that in the conventional art (FIG.27).

5. Operations of the Disk Recording and Reproduction Apparatus 100

The disk recording and reproduction apparatus 100 performs theoperations of 5.1 through 5.3 as initialization of the optical disk 1.The examination of the disk (5.1) is also referred to as the physicalformatting and usually performed once on one optical disk 1.

5.1: Examination of the Disk

5.2: LSN Assignment

5.3: Recording of Initial Data in the File System

After performing the initialization, the disk recording and reproductionapparatus 100 performs the operations of 5.4 and 5.5 each time a file iswritten or read.

5.4 Recording of Data (Recording of the File System and the File Data)

5.5 Reproduction of the Data

Hereinafter, the above-mentioned operations will be described in detail.

5.1 Examination of the Disk

Examination of the disk is performed at least once before recording datain the optical disk 1 in order to guarantee the quality of the opticaldisk 1. When the number of the defective sectors per optical disk isreduced to several by the improvement in production technology ofoptical disks, it will not be necessary to examine all optical disks tobe shipped. It will be sufficient to examine sampled optical disks.

The examination of the disk is performed by writing data on a specifictest pattern in all the sectors of the disk and then reading the datafrom all the sectors. Such examination of the disk is also referred toas “certify processing”.

In the examination of the disk, the slipping replacement algorithm isexecuted. As a result, one or more defective sectors are registered inthe PDL.

FIG. 11 is a flowchart illustrating a process of examination of thedisk.

In step 1101, the address of a first sector of the user area 6 is set asa writing address. In step 1102, it is determined whether the sectoraddress has been normally read or not. The reason why this is determinedis that, since the sector address needs to be read in order to write thedata in the sector, the data cannot be written in the sector if an erroroccurs in reading the sector address.

When it is determined that an error has occurred in reading the sectoraddress in step 1102, the physical sector number of the defective sectoris stored in a first defect list (step 1111).

When it is determined that no error has occurred in reading the sectoraddress in step 1102, specified test data is written in the sector atthe writing address (step 1103).

In step 1104, it is determined whether the writing address is a lastaddress or not. When the writing address is determined not to be a lastaddress, “1” is added in the writing address (step 1105). Then, theprocessing goes back to step 1102. Such processing is repeated; and whenthe writing address reaches the last address, the processing goes tostep 1106.

In step 1106, the address of the first sector of the user area 6 is setas a reading address. In step 1107, data on the reading address is read.In step 1108, it is determined whether the read data is identical withthe written data or not (i.e., whether the data was successfully writtenor not).

When it is determined an error has occurred in writing the data in step1108, the physical sector number of the defective sector is stored in asecond defect list (step 1112).

In step 1109, it is determined whether the reading address is the lastaddress or not. When the reading address is determined not to be thelast address, “1” is added in the reading address (step 1110). Then, theprocessing goes back to step 1107. In step 1108, error determination isperformed. Such processing is repeated; and when the reading addressreaches the last address, the first defect list and the second defectlist are put together into one list (step 1113). The PDL is created bysorting the sectors in the list in the order of the physical sectornumber (step 1114). The PDL is recorded in the disk information area 4together with the DDS (step 1115).

5.2 LSN Assignment

The LSN assignment is performed as described with reference to FIGS. 7and 8. When a defective sector is registered in the PDL, the assignmentof the LSNs is slipped in the direction toward an inner portion from anouter portion of the optical disk 1, with the location of the sector towhich the last LSN is assigned being fixed. A sector to which LSN:0 isassigned is determined, and then the physical sector number of thesector to which LSN:0 is assigned is stored in the DDS.

FIG. 12 is a flowchart illustrating a process of finding the physicalsector number of the sector to which LSN:0 is assigned.

As initial setting, the physical sector number of the first sector ofthe user area 6 is substituted into a variable UTSN (step 1201). Thevalue of the variable UTSN is written in the DDS in a later step.

Next, the value of the variable UTSN is substituted into a variable TOP(step 1202), and the physical sector number of the last sector of asearch area is substituted into a variable END (step 1203). The searcharea is an area, the number of the defective sectors in which needs tobe found. During a first loop, the physical sector number of the firstsector of the user area 6 is substituted into the variable TOP, and thephysical sector number of the last sector of the user area 6 issubstituted into the variable END.

Based on the variable TOP and the variable END, the number of thedefective sectors included in the search area is calculated (step 1204).For example, the number of the defective sectors included in the searcharea is given as a return value SKIP of a function FUNC (TOP, END).

The value of the variable UTSN is reduced by the return value SKIP. Thatis, UTSN=UTSN−SKIP is executed (step 1205). Thus, the physical sectornumber of the sector positioned at a location, obtained by skipping bythe number of the defective sectors included in the user area 6 from thefirst sector in the user area 6, can be obtained.

Steps 1202 through 1205 are repeated until it is determined that thereturn value SKIP matches 0 in step 1206, in order to deal with the casewhere a sector in the spare area 7 is registered in the PDL as adefective sector.

The value of the variable UTSN obtained in this manner indicates thephysical sector number of the sector to which LSN:0 is to be assigned.Accordingly, the value of the variable UTSN is stored in the DDS as thephysical sector number of the first sector of the user area 6 (step1207).

FIG. 13 is a flowchart illustrating a process of the function FUNC(TOP,END) in step 1204 shown in FIG. 12. The function FUNC (TOP, END) isrealized by finding the number of entries in the PDL in the search area.

As initial setting, 0 is substituted into the variable SKIP, whichindicates the number of entries (step 1301), and the total number ofentries read from the PDL is substituted into a variable n (step 1302).

In step 1303, it is determined whether the value of the variable n isequal to 0 or not. When Yes, the value of the variable SKIP is returnedas a return value of the function FUNC (TOP, END) in step 1308. When thetotal number of entries in the PDL is 0, value 0 is returned as thevalue of the variable SKIP, and the processing is terminated. When No instep 1303, the processing advances to step 1304.

The physical sector number (PDE:n) of the n'th entry is read from thePDL (step 1304). In step 1305, it is determined whether or not the PDE:nis equal to or greater than the value of the variable TOP and also equalto or smaller than the value of the variable END. When Yes, the searcharea is considered to include a defective sector registered in the PDLand “1” is added to the value of the variable SKIP (step 1306). When Noin step 1305, the processing advances to step 1307.

In step 1307, “1” is subtracted from the value of the variable n, andthe processing goes back to step 1303. In this manner, the operations insteps 1303 through 1307 are repeated for all the entries included in thePDL. Thus, the number of the defective sectors in the search area can beobtained as the value of the variable SKIP.

FIG. 14 shows an example of assignment of the LSNs to the sectors. Inthe example shown in FIG. 14, it is assumed that the user area 6 has asize of 100000, the spare area 7 has a size of 10000, the number ofentries registered in the PDL by the examination of the disk (i.e., thenumber of the defective sectors detected by the examination of the disk)is four, and the four defective sectors were all detected in the userarea 6.

LSNs are assigned to the sectors in accordance with the slippingreplacement algorithm described above.

First, LSN:99999, which is a last LSN, is assigned to a sector having aphysical sector number:109999. Then, the LSNs are assigned to thesectors in a decreasing order toward an inner portion from an outerportion of the optical disk 1 (i.e., toward the spare area 7 from theuser area 6). No LSN is assigned to the defective sectors. Instead, theLSN which would be assigned to each defective sector is assigned to asector immediately before the defective sector. As a result, theassignment of the LSNs is slipped in the direction toward an innerportion from an outer portion of the optical disk 1 by the number of thedefective sectors.

In the example shown in FIG. 14, the user area 6 includes four defectivesectors I through IV as described above. LSN:0 through LSN:3, whichwould be assigned to the four sectors I through IV if the four sectors Ithrough IV were not defective, are assigned to four sectors in the sparearea 7, respectively, having physical sector numbers of 9996 through9999. The reason for this is that the assignment of the LSNs are slippedby the number of the defective sectors (four in this example).

The physical sector number:9996 of the sector to which LSN:0 has beenassigned is recorded in the DDS as the physical sector number of thefirst sector of the extended user area 6.

In FIG. 14, the sectors in the spare area 7 having the physical sectornumbers of 0 through 9995 are collectively referred to as an “LR sparearea”. The LR spare area is defined as an area in the spare area 7 towhich no LSN is assigned. The LR spare area is used as a replacing areain the linear replacement algorithm.

The physical sector number of the first sector of the LR spare area isfixed to 0. The physical sector number of the last sector of the LRspare area is obtained by subtracting 1 from the physical sector numberrecorded in the DDS. Accordingly, substantially no amount of calculationis required to access the LR spare area.

5.3 Recording of Initial Data in the File System

The disk recording and reproduction apparatus 100 records initial dataof the file system to the optical disk 1 in accordance with a logicalformat instructed by the upper level apparatus 200. The logical formatis represented using the LSN. The initial data is, for example, datarecorded in the system reservation area 11, the FAT area 12 and the rootdirectory area 13 (i.e., the file management area 10) shown in FIG. 3.

The area in which the initial data is recorded is managed by the upperlevel apparatus 200 using the LSN. Especially, a first sector of thesystem reservation area 11 needs to be a sector to which LSN:0 isassigned. Accordingly, the upper level apparatus 200 cannot instruct thedisk recording and reproduction apparatus 100 to record the initial dataunless the LSN is determined. The content of the initial data isdetermined by the upper level apparatus 200.

The defect management during the recording of the initial data isperformed in accordance with the linear replacement algorithm. Theprocessing for recording the initial data is identical with theprocessing for recording data in the file management area 10 describedbelow in section 5.4.2, and thus detailed description thereof is omittedhere.

5.4. Recording of Data (Recording of the File System and the File Data)

FIG. 15 is a flowchart illustrating a process of recording data to theoptical disk 1. The processing shown in FIG. 15 includes recording ofdata in the file data area 14 (steps 1501 through 1509) and recording ofdata in the file management area 10 (steps 1510 through 1517).

5.4.1 Recording of Data in the File Data Area 14

In step 1501, a writing address is set. The writing address is an LSN ofa first sector of the file data area 14 (i.e., recording area) in whichdata is to be written. The LSN is determined by the upper levelapparatus 200, referring to the FAT which manages locations of files andempty areas, and then is sent to the disk recording and reproductionapparatus 100.

The FAT is read from the optical disk 1 by the disk recording andreproduction apparatus 100 before data is written, and then is stored inthe main memory 204 of the upper level apparatus 200. The CPU 201 refersto the FAT stored in the main memory 204 to determine the LSN of thefirst sector of the recording area. The resultant LSN is stored in thememory 104 of the disk recording and reproduction apparatus 100 togetherwith a recording instruction command. The microprocessor 101 executesthe operations in the following steps based on the LSN stored in thememory 104.

In step 1502, it is determined whether the sector address has beennormally read or not. The reason why this is determined is that, sincethe sector address needs to be read in order to write data into thesector, the data cannot be written in the sector when an error occurs inreading the sector address.

When it is determined that an error has occurred in step 1502, thedefective sector is replaced with a normal sector in the LR spare area(FIG. 14) in step 1508.

When it is determined that no error has occurred in reading the sectoraddress in step 1502, data is written in a sector of the file data area14 designated by the LSN. The data is sent from the I/O bus 205 of theupper level apparatus 200, buffered in the memory 104, and written inthe file data area 14.

In step 1504, verify processing is performed. The verify processingrefers to reading data from the sector in which the data was written instep 1503 and comparing the read data with the written data orperforming an operation using an error correction code to check whetherthe data was successfully written or not.

In step 1505, it is determined whether an error has occurred or not.When it is determined that an error has occurred, the defective sectoris replaced with a normal sector in the LR spare area (FIG. 14) in step1509.

In step 1506, it is determined whether all the data has been recorded ornot. When it is determined that all the data has been recorded, awriting address is set at the next LSN (step 1507). Then, the processinggoes back to step 1502. Such processing is repeated. When it isdetermined that all the data has been recorded, the recording of thedata in the file data area 14 is completed.

FIG. 16 is a flowchart illustrating a process of replacement processingexecuted in steps 1508 and 1509 shown in FIG. 15.

In step 1601, a sector in the spare area 7 to which no LSN is assigned(i.e., a sector in the LR spare area) is used as a replacing sector.

In step 1602, data which was to be recorded in the defective sector isrecorded in the replacing sector. Although not shown in FIG. 16,operations corresponding to those in steps 1502 through 1509 in FIG. 15are performed in order to write the data in the replacing sector. Whenan error is detected when writing the data in the replacing sector,another sector in the LR spare area is used as the replacing sector.

In step 1603, the physical sector number of the defective sector and thephysical sector number of the replacing sector are registered in theSDL. Thus, the defective sector is associated with the replacing sectorused instead of the defective sector.

The optical disk 1 is not accessed to update the SDL each time theoperation in step 1603 is executed. In step 1603, the physical sectornumber of the defective sector and the physical sector number of thereplacing sector are stored in a defect list stored in the memory 104.After it is determined that all the data has been recorded in step 1506in FIG. 15, the SDL is created and recorded in the disk information area4. Processing time is shortened by minimizing the number of times ofaccessing the optical disk 1 in this manner.

5.4.2 Recording of Data in the File Management Area 10

After the recording of the data in the file data area 14 is completed,the data is recorded in the file management area 10. The reason for thisis that, since management data such as, for example, FAT is updated byrecording the data in the file data area 14, the updated management dataneeds to be recorded in the file management area 10.

The processing of recording the data in the file management area 10(steps 1510 through 1517 in FIG. 15) is identical with the processing ofrecording the data in the file data area 14 (steps 1501 through 1509 inFIG. 15) except for the content of the data and the recording area.Therefore, a detailed description of the recording of the data in thefile management area 10 is omitted.

FIG. 17 shows the correspondence between the physical sector numbers andthe LSNs after the slipping replacement algorithm and the linearreplacement algorithm are executed. The horizontal axis represents thephysical sector number, and the vertical axis represents the LSN. InFIG. 17, chain line 1701 indicates the correspondence between thephysical sector numbers and the LSNs when the user area 6 includes nodefective sector. Solid line 1702 indicates the correspondence betweenthe physical sector numbers and the LSNs when the four defective sectorsare registered in the PDL and two defective sectors are registered inthe SDL.

In the example shown in FIG. 17, two defective sectors are detected whenthe data is recorded in the file management area 10. The two defectivesectors are replaced with replacing sectors in the LR spare area in thespare area 7.

The file management area 10 is located in an area starting with LSN:0.It can be appreciated from FIG. 17 that the distance (number of physicalsectors) between the defective sector in the file management area 10 andthe replacing sector in the spare area 7 is significantly shortenedcompared to that of the conventional art (FIG. 27). For example, thedistance in this example (FIG. 17) is about 10000 whereas the distancein the conventional art (FIG. 27) is 100000 or more. The shorteneddistance enhances the access speed to the optical disk 1.

5.5 Reproduction of the Data

For reproducing the data, the upper level apparatus 200 refers to themanagement data such as, for example, FAT to search for the location ofa file. The upper level apparatus 200 instructs the disk recording andreproduction apparatus 100 to access the file management area 10 torefer to the management data. The disk recording and reproductionapparatus 100 accesses the sector to which LSN:0 is assigned, withcertainty. The physical sector number of the sector is recorded in theDDS. Accordingly, the disk recording and reproduction apparatus 100 canaccess the sector to which LSN:0 is assigned at a high speed byreferring to the DDS.

The upper level apparatus 200 instructs the reading location in the filedata area 14 to the disk recording and reproduction apparatus 100 usingthe LSN. The disk recording and reproduction apparatus 100 refers to thePDL and the SDL to convert the LSN designated by the upper levelapparatus 200 to a physical sector number and reads the data from thesector having the physical sector number.

As described above, in the first example according to the presentinvention, the spare area 7 is located radially inward from the userarea 6 of the optical disk 1. The assignment of LSNs is slipped in thedirection toward an inner portion from an outer portion, with thelocation of the sector to which the last LSN is assigned being fixed.The location of the sector to which the first LSN (LSN:0) is assigned isrecorded in the DDS.

The last LSN is not necessarily assigned to the last sector of the userarea 6. When the last sector of the user area 6 is a defective sector,the last LSN is assigned to a normal sector in the user area 6 closestto the last sector.

In the first example according to the present invention, the defectmanagement is performed on a sector-by-sector basis. Alternatively, thedefect management can be performed on a block-by-block basis, each blockincluding a plurality of sectors. In such a case, block numbers areregistered in the PDL and the SDL instead of the physical sectornumbers. The defect management can be performed by any appropriate unit.The same effect can be obtained regardless of the unit.

In the first example according to the present invention, the upper levelapparatus 200 and the disk recording and reproduction apparatus 100 areconnected to each other through the I/O bus 205. Alternatively, theupper level apparatus 200 and the disk recording and reproductionapparatus 100 can be connected to each other in any manner (e.g., withwires or in a wireless manner). The elements in the disk recording andreproduction apparatus 100 can be connected to one another in anymanner.

EXAMPLE 2

Methods for managing a defect of an optical disk which are preferable toAV files (Audio Visual Data Files; i.e., time-continuous video and audiodata files), for which real-time recording and reproduction is importanthave been proposed in, for example, Goto et al., InternationalPublication WO98/14938. According to such methods, when AV files arerecorded in the optical disk 1, defect management is performed using afile system which is managed by the upper level apparatus 200 withoutperforming replacement processing based on the linear replacementalgorithm.

Hereinafter, an example of a method for managing a defect of an opticaldisk according to the present invention applied to an AV file systemwill be described.

The information processing system has the structure shown in FIG. 1. Theoptical disk 1 has the physical structure shown in FIG. 2 and thelogical structure shown in FIG. 3. The file system is different from theMS-DOS file system described in the first example, but is commontherewith in that the file management area 10 is positioned at alocation in the user area 6 having a fixed LSN.

6. Operation of the Disk Recording and Reproduction Apparatus 100

The disk recording and reproduction apparatus 100 performs theoperations of 6.1 through 6. 3 as initialization of the optical disk 1.

6.1: Examination of the Disk

6.2: LSN Assignment

6.3: Recording of Initial Data in the File System

After performing the initialization, the optical recording andreproduction apparatus 100 performs the operations of 6.4 and 6.5 eachtime a file is written or read.

6.4 Recording of Data (Recording of the File System and the File Data)

6.5 Reproduction of the Data

The operations of 6.1, 6.2, 6.3 and 6.5 are identical with those of 5.1,5.2, 5.3 and 5.5, and will not be described in detail.

6.4 Recording of Data (Recording of the File System and the File Data)

FIG. 18 is a flowchart illustrating a process of recording data in theoptical disk 1. The processing shown in FIG. 18 includes recording of anAV file in the file data area 14 (steps 1801 through 1809) and recordingof the AV file in the file management area 10 (steps 1810 through 1817).

6.4.1 Recording of the AV file in the File Data Area 14

The upper level apparatus 200 issues an AV file recording command to thedisk recording and reproduction apparatus 100. The disk recording andreproduction apparatus 100 receives the AV file recording command andexecutes the processing of recording the AV file in the file data area14.

The processing of recording the AV file in the file data area 14 (FIG.18) is identical with the processing of recording the data in the filedata area 14 (FIG. 15) except for steps 1808 and 1809.

In step 1808, an area including a defective sector is registered in thefile management information as a defective area.

In step 1809, an empty area continuous to the defective area is set.Then, the processing goes back to step 1802.

As can be appreciated from above, the disk recording and reproductionapparatus 100 does not perform replacement processing even when adefective sector is detected when an AV file recording command isreceived.

FIG. 19 shows a data recording area 5 after the AV file is recorded.

It is assumed that an AV file referred to as “V1.MPG” (hereinafter,referred to as the “V1.MPG file”) is recorded in the file data area 14and a defective sector is detected in the AV file. In FIG. 19, adefective area including the defective sector is hatched. A1, A2 and A3represent a first LSN of each area, and L1, L2 and L3 represent a lengthof each area. The first LSN of the defective area is A2, and the lengththereof is L2.

The V1.MPG file is managed by a file management table stored in the FATarea 12. The file management table is linked with a file entry of theV1.MPG file stored in the root directory area 13.

The file management table includes therein the first LSNs and lengths ofthe areas in which the AV file is located. The file management tablefurther includes attribute data for identifying whether data has beenrecorded in the area or the area is a defective area in which no datahas been recorded. In step 1808 shown in FIG. 18, attribute data of anarea starting from LSN:A2 and having a length of L2 is set to be adefective area in which no data has been recorded. Thus, at the time ofreproduction, this area is recognized to be defective. As a result,reproduction of the defective area can be skipped.

In the example shown in FIG. 19, the file management table includesinformation on three areas on the V1.MPG file. The file management tableshown in FIG. 19 indicates that an area starting from LSN:A1 and havinga length of L1 and another area starting from LSN:A3 and having a lengthof L3 have data recorded therein and that the area starting from LSN:A2and having a length of L2 has no data recorded therein.

As can be appreciated from the above, the file management table allows adefective area to be identified based on the LSN. For reproducing theV1.MPG file, the AV file can be continuously reproduced while skippingthe defective area.

The recording based on the AV file recording command is performed on ablock-by-block basis, each block including a plurality of sectorsbecause the size of the AV file is relatively large. Accordingly, theinformation stored in the FAT area 12 and the root directory area 13 hasblock addresses. The size of the file system management information isreduced by managing the data on a block-by-block basis. Theblock-by-block recording can be performed by repeating sector-by-sectorrecording a plurality of times. Accordingly, the fundamental operationof the disk recording and reproduction apparatus 100 is similar to theoperation described above.

6.4.2 Recording of Data in the File Management Area 10

The processing of recording the AV file in the file management area 10(FIG. 18) is identical with the processing of recording the data in thefile management area 10 (FIG. 15). When a detective sector is detectedwhen the AV file is recorded in the file management area 10, replacementprocessing is performed in steps 1816 and 1817. The reason for this isthat the defective sector detected in the file management area 10storing the file management table cannot be logically managed by thefile management table.

When data for which real-time recording and reproduction is not veryimportant, such as, for example, computer data (hereinafter, referred toas the “PC data”) is recorded in the optical disk 1, the upper levelapparatus 200 issues a PC file recording command to the disk recordingand reproduction apparatus 100. The operations of the disk recording andreproduction apparatus 100 in this case are identical with theoperations of 5.1 through 5.5.

As described above, a method for managing a defect of an optical diskwhich is suitable to AV files is provided in the second exampleaccording to the present invention.

EXAMPLE 3

A ZCLV system information recording medium, in which the combined sparearea and user area is divided into a plurality of zones which havedifferent disk rotation speeds, such as a DVD-RAM disk or the like, hasa guard area on the border between adjacent zones.

FIG. 20 shows a physical structure of an optical disk 1 a havingtwo-zones. The optical disk 1 a has zone 0 in an inner part thereof andzone 1 located radially outward from zone 0. A guard area 2001 isprovided on the border between zones 0 and 1 so as to cover a part ofeach zone. A part 2001 a of the guard area 2001 in zone 0 and a part2001 b of the guard area 2001 in zone 1 each include at least one track.

The part 2001 a and the part 2001 b of the guard area 2001 have tracksof different structures. Accordingly, the signal quality in the guardarea 2001 is inferior, and therefore the guard area 2001 is not suitablefor recording. The guard area 2001 is set as an area in which no data isto be recorded. The locations and sizes of the zones 0 and 1 and guardarea 2001 are fixed based on the optical disk 1 a.

The structure of the information processing system is as shown in FIG.1. The logical structure of the optical disk 1 a is identical with thatof the optical disk 1 shown in FIG. 3.

FIG. 21 shows the correspondence between the physical sector numbers andthe LSNs after the slipping replacement algorithm is executed. Thehorizontal axis represents the physical sector number, and the verticalaxis represents the LSN. In FIG. 21, chain line 2101 indicates thecorrespondence between the physical sector numbers and the LSNs when theuser area 6 includes no defective sector. Solid line 2102 indicates thecorrespondence between the physical sector numbers and the LSNs when theuser area 6 includes four defective sectors.

As shown in FIG. 21, no LSN is assigned to the defective sectors. Theassignment of the LSNs are slipped in the direction toward an innerportion from an outer portion of the optical disk la (i.e., in thedecreasing direction of the physical sector number) as in the first andthe second examples.

As also shown in FIG. 21, no LSN is assigned to the guard area 2001. Theassignment of the LSNs is performed so that the LSNs are continuousbetween two ends of the guard area 2001. Accordingly, data is notrecorded in the guard area 2001.

The spare area 7 and the file management area 10 having a first sectorto which LSN:0 is assigned are located in the same zone. Accordingly,the processing of replacing a defective sector which is detected whenthe data is recorded in the file management area 10 can be performed ina single zone, without requiring a seek operation across the borderbetween the zones.

In a DVD-RAM disk, an error correction code is calculated over aplurality of sectors. Therefore, the plurality of sectors is defined asone block. For example, an ECC block includes 16 sectors. In such acase, the optical disk is designed so that multiples of the block sizeare equal to the size of each zone. However, when LSNs are assigned inaccordance with the slipping replacement algorithm, one block canpossibly be located over two zones across the guard area 2001 dependingon the number of detected defective sectors. The reason for this is thatthe number of LSNs assigned to each zone varies in accordance with thenumber of the defective sectors.

FIG. 22A is a conceptual view of a slipping replacement algorithmexecuted by the disk recording and reproduction apparatus 100 (FIG. 1)on the optical disk 1 a. In FIG. 22A, each of the rectangle boxesrepresents a sector. Characters in each sector represent an LSN assignedto the sector. The rectangle boxes having an LSN represent normalsectors, and the hatched rectangle boxes represent a defective sector.In the example shown in FIG. 22A, an ECC block for calculating the errordetection code includes 16 continuous sectors. However, the number ofthe sectors included in the ECC block is not limited to 16. An ECC blockcan include any number of sectors.

Reference numeral 2201 represents a sequence of sectors including nodefective sector in the user area 6. Reference numeral 2202 represents asequence of sectors including one defective sector in the user area 6(with no block correction). Reference numeral 2203 represents a sequenceof sectors including one defective sector in the user area 6 (with blockcorrection). Block correction will be described below.

When a last sector in zone 1 is a normal sector, the last LSN:m isassigned to the last sector of zone 1. LSNs are assigned to theplurality of sectors included in the user area 6 in a decreasing orderfrom the sector to which the last LSN:m is assigned.

When the user area 6 includes no defective sector, LSN:m through LSN:0are sequentially assigned from the last sector to the first sector inthe user area 6 as represented by the sequence of sectors 2202.

When a sector in the sequence of sectors 2201 to which LSN:i is assignedwas a defective sector, the assignment of the LSNs is changed so thatLSN:i is not assigned to the defective sector but to a sectorimmediately before the defective sector. Thus, the assignment of theLSNs is slipped by one sector in the direction toward the spare area 7from the user area 6. As a result, LSN:0 is assigned to a last sector ofthe spare area 7 as represented by the sequence of sectors 2202.

In the sequence of sectors 2202, an ECC block to which LSN:k throughLSN:k+15 areas signed is located over the zones 0 and 1 across theborder. In order to prevent one ECC block from being located over two ormore zones, block correction is performed.

A sequence of sectors 2203 is obtained as a result of block correctionperformed on the sequence of sectors 2201. The sequence of sectors 2202includes one defective sector in zone 1. In this case, the sector 2203is obtained by slipping the LSN assignment to the sequence of sectors2202 by 15(=16−1) sectors in the direction toward the spare area 7 fromthe user area 6.

As described above, when the user area 6 includes a defective sector,block correction of the LSN assignment is performed so that the firstsector of each zone matches the first sector of the ECC block of thezone. Such an operation prevents one block from being located over aplurality of zones. As a result, an access to a plurality of zones doesnot occur when recording and reproduction is performed to and from oneblock. This allows the time period required for recording orreproduction of data to be shortened. This also allows data in one blockto be read continuously. Therefore, a memory for calculation and anoperation apparatus which are required for preliminary pipelineprocessing can be curtailed without disturbing the pipeline processingof error correction.

FIG. 22B shows the correspondence between the physical sector numbersand the LSNs after the slipping replacement algorithm described withreference to FIG. 22A is executed. The horizontal axis represents thephysical sector number, and the vertical axis represents the LSN. InFIG. 22B, chain line 2211 is identical with chain line 2101 in FIG. 21,and dashed line 2212 is identical with chain line 2102 in FIG. 21.

It is assumed that, as a result of performing assignment of the LSNsrepresented by dashed line 2212, one block is located across the guardarea 2001; i.e., a part of the block is located in zone 0 and the restof the block (fraction of the block) is located in zone 1.

In this case, the assignment of the LSNs is performed in an increasingdirection by the fraction of the block located in zone 1. Due to suchassignment, the block located across the guard area 2001 is entirelylocated in zone 0, and the first sector of the next block is located asthe sector immediately after the guard area 2001 of zone 1. Accordingly,the first sector of the block can be located as each of recordable firstsector in each zone with certainty.

Solid line 2213 in FIG. 22B shows the results of the assignment of theLSNs. As can be appreciated, as a result of the assignment of the LSNs,the LSNs corresponding to the fraction of the block are assigned to thesectors in zone 0. As can be appreciated, the assignment of the LSNsrepresented by solid line 2213 prevents the block from being locatedacross the guard area 2001.

In the optical disk 1 a, the location of the sector to which LSN:0 is tobe assigned is calculated as a location fulfilling a prescribed capacity(4.7 GB), with the location of the sector to which the last LSN isassigned being fixed. The location is calculated based on the number ofthe defective sectors-detected in each of the plurality of zones. LSN:0is assigned to the sector positioned at the resultant location. Thephysical sector number of the sector to which the LSN:0 is assigned isstored in the entry of the DDS.

The LSN assigned to the first sector of each zone is stored in the entryof the DDS. By this operation, a high speed access to the first sectorof each zone is realized without calculation.

FIG. 22C shows a structure of the DDS. The DDS includes entries forstoring the LSNs assigned to the first sector of each zone. The numberof the entries is equal to the number of zones. For example, when theoptical disk 1 a includes two zones (zone 0 and zone 1), the DDSincludes an entry for storing an LSN assigned to the first sector ofzone 0 and an entry for storing an LSN assigned to the first sector ofzone 1.

As described above, in the third example according to the presentinvention, a method for managing a defect of an optical disk having aplurality of zones is provided. Also provided in the third exampleaccording to the present invention is a method for managing a defect ofsuch an optical disk for, when block-by-block recording is performed,preventing a block from being located across a guard area.

In the third example, the optical disk 1 a has two zones. Alternatively,the optical disk can have three or more zones. Also, in such cases, LSNscan be assigned to sectors so that the first sector of the block islocated as the recordable first sector of each zone.

As described above, according to an information recording medium of thepresent invention, a spare area is located radially inward from a userarea. When a defective sector is detected in a file management arealocated in the vicinity of LSN:0, the defective sector is replaced witha replacing sector in the spare area in accordance with the linearreplacement algorithm. Since the distance between the defective sectorand the replacing sector is relatively small, a delay in access causedby the defective sector is relatively small. The file management area,which is accessed frequently, has a high possibility of including adefective sector. Accordingly, the above-described reduction in thedelay in access caused by a defective sector detected in the filemanagement area is significantly effective in shortening the time periodrequired for recording or reproducing data.

A physical sector number of the sector to which LSN:0 is assigned isstored in a disk information area. The physical sector number of thefirst sector in the replacement area (LR spare area) used in the linearreplacement algorithm is fixed. The physical sector number of the lastsector in the LR spare area may be determined by subtracting “1” fromthe physical sector number recorded in the disk information area.Accordingly, the location of the LR spare area can be obtained withsubstantially no calculation by referring to the physical sector numberrecorded in the disk information area.

When the information recording medium is divided into a plurality ofzones, the defective sector detected in the file management area and thereplacing sector are located in the same zone. Accordingly, no access tothe file management area is to a plurality of zones. Thus, the timeperiod required for recording or reproduction of data can be shortened.

When block-by-block recording is performed, the first sector of theblock can be located as a recordable first sector in each zone.Accordingly, an access to a plurality of zones does not occur whenrecording to and reproduction from one block. This allows the timeperiod required for recording or reproduction of data to be shortened.This also allows data in one block to be read continuously. Therefore, amemory for calculation and an operation apparatus which are required forpreliminary pipeline processing can be curtailed without disturbing thepipeline processing of error correction.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

What is claimed is:
 1. An information recording medium, comprising: adisk information area; a user area including a plurality of sectors; anda spare area including at least one sector which, when at least one ofthe plurality of sectors included in the user area is a defectivesector, is usable instead of the at least one defective sector, wherein:the spare area is located radially inward from the user area, and thedisk information area includes a defect management area which includesan area for recording a physical sector number of the defective sectorand a physical sector number of the replacing sector in which data isrecorded instead of the defective sector.